While others take shelter as a tornado approaches, storm chasers venture into danger.

Sometimes they're scientists collecting invaluable data. But a growing number are amateurs armed with little more than a smartphone, a digital camera and a desire to sell 15 seconds of video.

The deaths of three respected researchers near Oklahoma City last week have renewed questions over whether the risk is too great — regardless of the adrenaline rush one gets from nature's worst weather.

Storm chasing has proliferated across Tornado Alley as advanced technology becomes available to untrained weather enthusiasts.

And efforts to provide critical field data that can't be gleaned from radar are in competition with tornado paparazzi that speed from storm to storm.